Starting mechanism for gas engines



- July 29, 1924.

1503;075 1.. M.- TAYLOR v STARTING MECHANISM FOR GAS ENGINES Filed April 29, 1915 INVENTOR' l ATTORNEY esfer/ f fay/0k atented July 29, 1924.

LESTER M. TAYLQR, 0F WILKINSBURG, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA. I

STARTING MECHANISMMFQR GAS ENGINES.

Application filed April 29, 1915. Serial No. 24,750.

To all whom it may concern:

Be it known that I, LESTER M. TAYLOR, a citizen of the United States, and a resident of lVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Starting Mechanisms for Gas Engines, of .which the following is a specification. t i Y.

My invention relates to starting mechanisms for gas engines, and it has particular reference to such mechanisms as embody screw-threaded shafts for automatically effecting the operative connection of starting motors to the shafts of internal combustion engines.

Oneobject of my invention is to provide a simple means for preventing the oscillation of a spring which connects two relatively rotatable shafts incident to variations in load connected to one of said shafts.

A second object of my invention is to pro- 'vide a simple and eiiicient means for firmly securing the respective ends of a connecting spring to two relatively rotatable shafts.

A further object of my invention is to provide a simple means for frictionally engaging a pinion at the end of its path of longitudinal movement on a screw-threaded shaft.

In the operation of starting mechanisms of the same general character as that of my invention, it has been found that the variations in-torque required to rotate an engine shaft as the engine approaches or recedesfrom each of its several compression points, causes a spring, which resiliently connects the screwthreaded shaft to the motor, to be alternately contracted and expanded. The variations in load set up oscillations of the spring Which'have the efiect of tending to periodically effect the disconnection of the pinion from the fly wheel.

It has also been found, in practice, that it is difficult to so secure the connecting spring to the relatively rotatable shafts which it connects that the force to which it is subjected upon the back firing of the engine will not cause the spring to be disconnected from the shafts. Another disadvantag'e incident to the use of some of the arrangements heretofore proposed is that the pinion, which is actuated longitudinally on a screw-threaded shaft by relative rotation of the parts, is actuated outwardly with such force that it strikes, with considerable impact, the collar which limits its outward movement.

I provide a split sleeve which is interposed between the helical spring and the relatively rotatable shafts which it connects. When the spring is contracted by relative movement of the shafts, it first engages the resilient split sleeve, and further relative movements of the several convolutions' of the spring are opposed by their frictional engagement with the sleeve. The resilient force of the sleeve is also added to that of the spring to'resist relative movement of the shafts.

When the spring is contracted to such a degree that the split sleeve is caused to firmly grip the adjacent ends of the relatively rotatable shafts, relative movement between them is prevented or materially limited bevcause of their frictional connection by the This construction operates resilient sleeve. to prevent or damp out the oscillation of these parts which are due to the variations in load above described. The gripping action of the sleeve operates, also, to relieve the spring of some of the load, as the ends of the shafts are, to some extent, directly connected. Concentration of the load at the terminal loops or anchoring ears of the spring is thereby prevented.

I provide alsoa spring which has terminal loops of such form that the spring cannot be disconnected from the shafts by back firing of the engine and which afford a convenient means for firmly securing the respective ends of the spring to the shafts; A resilient washer or buffer spring frictionally engages the pinion during a portion of its path of movement upon the screw-threaded shaft to exert a wedging action of the pinion with respect to the screw threads at the outer endof the screw-threaded shaft. The wedgin action tends to prevent the disconnection o the pinion from the fly wheel when the engine recedes from its compression points.

The details of my invention will be def'scribedin connection with the accompany- Ping drawings, in which Fig. 1 is a side view, partially in elevation and partially in section, of a starting mechanism constructed in accordance with my invention, part of the 3, the plane of an engine fly wheel-1 is inrounds their adjacent ends.

dicated by dot and dash lines in Fig. 1. A starting motor 2, which may be, for example, an electric motor, may be secured to the frame of an automobile or other motor vehicle in any. suitablemanner. The motor armature shaft 3'is'provided with a pinion 4 which meshes with a gear wheel 5 on a short countershaft 6. A shaft 7 is mo'unted'in axial alinement with the shaft 6 and is rotatably connected thereto by means of a reduced portion 8 which projects into a longitudinally extending bore .9 1n the shaft 6.

The shafts '6- and 7 are resiliently connected by a helical spring 10 which sur- The inner end of the spring 10 is bent to form a loop 11 which projects into' a recess 12 that is formed in the gear wheel 5. The loop portion 11 is connected to the shaft 6 by means of a stud 13'which projects into the recess 12. The end portion 14 of the spring 10 extends adjacent to the outer face of the gear wheel 5 and substantially plane to its surface. The opposite end portion of the spring comprises a plurality of loops 15 and 16 which respectively engage a bolt 17 and astud 18. The loop portions 15 and 16 form a terminal portionof substantially, S-shape.

A cylindrical split sleeve 19 of resilient 'material. an end view of which is shown ,in Fig. 3, surrounds the adjacent end portions of the shafts 6 and and is interposed between the shafts and the spring 10. The internal diameter of; the split sleeve is slightly greater than the diameters of the shafts 6 and 7, so that, normally, the

shafts are not engaged by the sleeve. Whenthe internal diameter of the spring 10 is decreased,.the sleeve 19 is caused to firmly engage the shafts 6 and 7 to prevent their contraction of the spring. Such occur-.

relative movement.

The prov sion of the sleeve member 19 in- 6 sures, also, that. convolutions of thespring are not drawn into the space between the ends of the shafts 6 and 7 in case of relative axial movement of the shafts and the rences-have caused the failure of many spring and the sleeve.

springs in, the operation of devices of this character. a r

-The shaft 7 is .provided with a screwthreaded portion 20 u on which is mounted a weighted pinion 21Qor longitudinal move-.'

ment thereon into and out of operative engagement with the fly wheel 1. The shaft 8 is provided with ,a collar member 22 at the outer extremity of-the screw-threaded portion 20, adjacent to which is mounted a resilient washer or buffer spring 23 which serves not only to prevent the wedging action between the screwsthreads and the collar member 22, but to receive the impact of the pinion 21 as it is forcibly actuated longitudinally on the shaft.

Normally, the various parts are their respeotive illustrated positions, with the The shaft 7 will be the inertia of the weighted pinion 21, the I shaft 7 will rotate relatively to it and it will be actuated to the left into engagement with the fly' wheel 1. As above stated, the impact of the pinion 21 will be absorbed by the buffer spring 23 which also causes the pinion to frictionally engage the screwthreaded shaft during the latter portion of The pinion 21 then rotates with the shaft 7 to crank the en its outward movement.

gine.

As the engine approaches each of its several compression points, an increased torque is necessary to rotate the engine shaft. Accordingly, the spring 10 will be contracted as the shafts 6 and 7 rotate relatively, the one to the other, and the spring will engage the split sleeve member 19.

The tendency of the spring to further contract is then opposed by its frictional engagement with the sleeve and by the resilient force of the latter. Should the torque necessary to rotate the engine shaft be such that the spring is contracted to such degree that the sleeve engages the adjacent ends of the shafts 6 and 7, relative rota table movement of these parts is further opposed by the frictional engagement between them and the sleeve.

As the engine recedes from the compression points, the frictional engagement of these parts is maintained for a'material portion of. the expansive-movements of the The sleeve operates, therefore, to damp'out oscillations of the spring and the shafts 6 and 7 that are caused by periodic variations in the torque required to rotate the engine shaft. Con-- siderable torque is transmitted throu h the sleeve, thereby relievingvthe spring rom ,a portion of its load which would otherwise beconcentrated at the terminal loops. The

' latter constitute the weakest part of the spring. Disconnection of the pinion from the fly wheel during the moyement of the engine from the compression 'points is prevented by the wedging action of the pinion and the screw-threaded shaft produced by the bufier-spring washer.

' When the engine starts under its own i power, the fly wheel 1 will rotate at a higher rate of speed than it .was driven by the motor, and the pinion 21 will be caused to overrun the shaft 7. The pinion 21 will, therefore, be actuated to the right to its illus-' trated position, out of engagement with the fly wheel. If the engine becomes the driving member because of a failure to disconnect the pinion from the fly wheel, the spring 10 cannot be disconnected from the shafts 6 and 7. The end portion 14, which is a .continuation of the loop portion 11, effectually prevents the inner end of the spring from being withdrawn through the recess 12 in the gear wheel 5.

'At the other end of. the spring, the loop portions 15 and 16 new arranged that, when the motor is the driving member, the

' f torque is transmitted through the loo portion 15 and the bolt 17, the loop portion 16 and the stud 18 preventing the opening of the loop portion 15 even though back-firing of the en 'ne should occur. In case the bolt 17 shoul become loosened, or the'loop por-' tion 15 should become disconnected from it, the torque will be transmitted by the loop portion 16 and stud 18, and uncoiling of the loop 15- is prevented. When the fly wheel is the driving member, the torque is also trans mitted by the loop portion 15"and thebolt 17. The end of the spring is securely anchored by means of the loop 16 and the stud It will be obvious, therefore, that a 'movement'of the end portion of the sprin relativelyto the bolt 7 and the stud 18, sh ficientto efl'ect its disconnection therefrom, is, positively prevented.

Reference may now be had to Figs. 4 and V 5, in which is illustrated a modification of my invention. A shaft 27, which is provided with a screw-threaded portion 28 and a buffer spring 23, is, adapted to be driven through a mechanism comprising a frictionclutch. The clutch mechanism comprises a ear wheel 29 that is mounted on the shaft 27 tween two collar members 30 and 31 and I is yieldingly connected thereto by means of disks 32 of any suitable friction material. The frictional en agement of these several parts is controlle bythe angular. sition of the collar 31 relatively to a reduce screwbuffer spring.

threaded portion of the shaft 27. Move ment of the collar 31, relative tothe shaft 27, after these parts have been adjusted, is

prevented by a locking device which may be, for example a key 33, having radially extending arms which engage alined slots in the ends of the shaft 27 and the hub portion of the collar 31. The key is held in position by a suitable screw 34.

It will be noted that I provide a simple arrangement whereby oscillations of the several relatively rotatable parts are prevented during the operation of cranking the engine. The tendency of the pinion to become isconnected from the fly wheel when the engine recedes from its several compression points, is prevented by the provision of a The disconnection of the spring from the parts which it connects by the uncoiling of its end portions, is avoided by the use of the terminal loops arranged in accordance with my invention. These and otheradvantages will be apparent to those skilled in the art to which my invention appertains. Y

I claim as my invention:

1. In a starting mechanism, the combine-I tion with a motor-driven shaft, and a shaft in axial alinement therewith, of a s ring for connecting said shafts, and a resilient member between said shafts and said spring.

2. In a starting mechanism, the combination with a motor-driven shaft, and a shaft in axial alinement therewith, of a spring for connecting saidshafts, and a resilient sleeve member between said shafts and said spring.

3. In a'starting mechanism, the combination with afmotondriven shaft, and a shaft I threaded shaft. of a spring for connecting said shafts, said spring having a terminal portion of substantially S-shape, and means connected to oneof said shafts for engaging the loops of said terminal portion.

6. In a starting mechanism, 'the combination with a motor-driven shaft, and a screwthreaded shaft, of a spring for connecting said shafts, said s ring comprising a plurality of loop portions at one end thereof, and means on one of said shafts for engaging said loop portions.

7. In a starting mechanism, the combination with a motpr-driven shaft, and a shaft in axial alinement therewith,- of a spring for connecting said shafts, and a member between said shafts and said spring for snecessively engagin the convolutions of said sprin and said shafts.

8. in a starting mechanism, the combination with a motor-driven shaft, and a shaft in axial alinement therewith, of a spring for connecting said shafts, and means for 10 successively retarding contractile movement of said spring and relative movements of said shafts.

In testimony whereof, I have hereunto subscribed my name this 26th day of April,

LESTER M. TAYLOR. 

